Central Heating

[Farmoorlad]

My central heating keeps going on and off. I use the thermostat in the morning to switch it on and then thermostat to switch it off at night. The central heating has now gone off altogether regardless of the thermostat setting and temperature. It will then switch itself off without warning and then back on again at its own reasonng. I have had two plumbers out to fix it but just before they arrived the central heating switched itself on meaning they could not check for a fault. They replaced a small item near the pump but that has had no effect. Any help cos its freezing in here. Best regards. Gordon

[gucciman]

haven't you got a time programmer for your heating? why do you use the thermostat?

[RAYMAN]

Is it a combi or other type of boiler?

Has the plastic tube come off the air flow switch[combi]

Has your pump stuck

Have you bled your your radiator which acts as a heat bypass normally fitted in the bathroom.

Is your hot water working? maybe the 3way actuator is stuck.

http://www.diynot.com/forums/search.php?mode=results

Try this site for your questions

[Farmoorlad]

I use the thermostat as I want a constant temperature all day of 20 C and 15 C at night.

All the things you mention have been checked but seem to be ok

[stanleyman]

This seems like an intermittent fault and most likely electrical. Common faults are, loose connectors in the programmer where the pins fit in, just tighten up slightly. Dirt in the thermostat contacts, clean. Faulty microswitch in the motorvalve head, replace. Check for loose or broken wires, fuse etc. in plugs and junction boxes. Does the hot water work ok and is there power to the programmer?

[Farmoorlad]

Yes hot water works fine all the time when needed even tho CH isn't working. I too think it is electrical and will try all your suggestions. Thanks. Try telling that to a plumber tho lol. Brrrrrrrr

[stanleyman]

Well that's a help at least we know the boiler and system is working. You need to find where the power is not getting to the motorvalve that controls the heating. You can do this with a neon tester.

Start at the thermostat to see if there is power in and out of it, then work backwards or forwards according to what you find. Does overriding the motor valve with the lever on the side make any difference? Could be just a failed syncronmotor in the head but don't rule out other electrical problems in the heating line.